Processes for the production of dibasic and monobasic acids



United States Patent PROCESSES FOR THE PRODUCTION OF DIBASIC AND MONOBASIC ACIDS Allison Maggiolo, Merion, Pa., assignor to The Welsbach Corporation, Philadelphia, Pa., a corporation of Delaware No Drawing. Application March 6, 1956 Serial No. 569,673

3 Claims. (Cl. 260-406) This application cation Serial No. abandoned.

Processes for the is a continuation-in-part'of 522,395, filed my appli- July 15, 1955, and now excessive consumption of ozone. In this German patent temperatures up to 150 C. are employed.

British Patent No. 741,739 of December 14, 1955 disnent examples are:

(.1) Certain ozonides can decompose in two ways as a result of the presence or absence of water, see Briner, Helv. Chim. Acta 21, p. 748 (1938).

(2) Ozonides containing oxygen in other parts of the see Straus, Ann. 393, p. 235 (1912).

(5) A proposed mechanism of ozonide decomposition which begins with the presence of water has been shown by Harries, Ann. 374, p. 288 (1910).

Most unexpectedly I have found that the presence of water in the ozonolysis of unsaturated fatty acids does' not adversely afiiect the yield of carboxylic acids obtained therefrom.

I have found further and most unexpectedly .that if the ozonolysis of the unsaturated fattv acid is conducted at temperatures in the range of 049 C. and preferably in the range of approximately 15-30 C. in the presence pected increase in 2,865,937 Patented Dec. 23, 1958 2 of water and, thereafter, if the ozonides are oxidized at higher temperatures above C. and up to C. in the presence of water and ozone of from 15 to 20%.

Considerable heat is evolved in the ozonolysis of unsaturated compounds. Inparticular, it has been established with respect to the present type of reaction that preferably in the range of approximately 15-30 the presence of water and ozonides is completed and C. and C. in

then subjecting the ozonides to temperatures of approximately C., in the presence of water to proved production of the acids.

Another object of the present invention is to provide such novel processes in which water is employed with the reactants in the ozonolysis step to remove the heat of re- 100 C., and up to 150 obtain increased and im- Other and further objects of the present invention will appear from the following description of illustrative embodiments thereof.

These illustrative embodiments of the present invention are described should in no way be construed as defining or limiting the invention, reference being had to the appended claims to determine the scope thereof. 1

As noted above, the processes of the present invention include as a first step for the decomposition of the resulting ozonides also in the presence of water. The ozonization step is performed by passing an ozone-oxygen or ozone-air mixture into the added C. and the following oxidative decomposition step is carried out at higher temperaturesup to 150 C. an unex the amount of acids producedis-obtained as will more fully appear hereinafter.

The experimental results of Table I show thatthe some increase in yield is water is 5 to 6 times the Table I also shows that external cooling must be m vided to maintain the reactor temperature at 30 C. when the water content is 20% or less. However, when water is present in the range from approximately 100 to 600% no external cooling is necessary, and the temperature of.

the reactor did not exceed 46 0.

TABLE I Ozonization of tall oil fatty acid in caproz'c acid Yield in Water 1 Max. Percent of No. of Trials in Wt. Temp. Theoretically Percent Reactor, obtainable C. Dlbasic Acid These ozonides were then subjected to oxidative decomposition in the presence of water as expressed by the following equations:

O H2O GH;(CH2)2CH CH(CHa)1CO H %0, -r

CHKCHMC 01H H020 (CH2)1C 0 B Pelargonic acid Azelaie acid Little or no malonic acid is formed although the formation of thisacid might be expected and the disposition of the three-carbon linkage between the two ozonide groups is therefore unknown.

More specifically, in the process described above 56 g. (0.20 moles) (0.30 equivalent of double bond) tall oil unsaturated fatty acids (U. F. A.) in solution in 60 gm. of caproic acid is placed in a cylindrical glass vessel having a fritted glass bottom and connected'at the top to a cold finger condenser, an absorber containing 100 ml. of 5% aqueous potassium iodide solution, and a wet test meter in series. Calculated amounts of water up to 600% by weight of the reactants and solvent are added so that the reactionin the glass vessel can he conducted at a controlled temperature in the range of approximately 15-30 C. Ozonolysis is then carried out by admitting a stream of oxygen containing approximately 1-6% ozone by weight to the glass vessel through the tritted plate at approximately 0.050 C. F. M. for approximately three hours and until the iodide test solution turns redbrown indicating the presence of ozone and an essentially completed reaction.

The ozone concentration is then reduced to to A 7 without interruption to the oxygen stream which maybe reduced to 0.01 C. F. M. and oxidation of the ozonides in the glass vessel is continued for approximately three and a half hours. During this oxidation step the temperature in the glass reaction vessel should be raised to approximately 100-110" C. by heating coils surrounding the glass vessel.

At the end of the oxidation step the mixture in the glass vessel is cooled and transferred to a distilling flask where it is distilled at -20 mm. Hg. The fraction of monobasic acids distilling at 160 C. amounting to 81.5 g. are chiefly caproic and pelargonic acids.

The stripped residue is then boiled and the resulting aqueous layer separated from the oily layer. The cooled aqueous solution deposits almost pure azelaic acid, neutral equivalent 95-96. Azelaic acid should also be extracted from the oily layer and the total yield of almost pure azelaic acid approximates An inferior grade of crude azelaic acid amounting to approximately 10- 15% may be isolated from the mother liquors. The yield of almost pure azelaic acid in accordance with this embodiment of the present invention reflects an improvement of approximately 15% over previous known methods and particularly that of German patent.

Oxidants other than oxygen or air may be used to advantage in this process as shown in Table II:

TABLE II Oxidation of tall oil fatty acid ozonide comparison of different oxidants Oxldant Percent Average Yield 1 Air only 2g 69 Air-O3 70 72 ()zonly 70 7O Or-Ofi 75 I Based on theoretically obtainable dlbasic acid. 9 Best run. 3 Mo to %0 percent by weight.

Table II shows that when ozone in amounts of from to by weight is present in the oxidizing gas the yield of dibasic acid is improved.

Comparing the processes of the present invention more specifically with those of the German patent the pro cedure of this patent was followed in detail with a mixture of oleic acid, water and acetic acid which was ozonized at 60 C. with a yield of 60% high-grade azelaic acid. An identical mixture was then treated in accordance with the present invention and was ozonized at 25 C. in the presence or water until one mole of ozone per mole of unsaturation had been added. The temperature was then raised during the oxidative decomposition step and the reaction was completed in the manner described in the German patent again in the presence of water. A yield of 70% high-grade azelaic acid was obtained.

The same procedure, as above, was carried out utilizing tall oil fatty acids, caproic acid, and water which were ozonized at 70 C. in accordance with the German patent producing a yield of 63% high-grade azelaic acid.

75 Anidentical m re wa trea ed a i e'c d e with the German patent and produced a yield of 34.4%

ozonolysis reaction temperatures which in every way satisfy the objects described above.

Changes in or modifications to the illustative embodiments of the processes of the present invention described Reference should therefore be had to the appended claims to determine the scope of the invention.

What is claimed is:

1. In a process for the production of dibasic and monothe group consisting of oleic acid, linoleic acid and mix- 40 tures of oleic acid and linoleic acid the steps of ozonizing the unsaturated fatty acids in the presence of Water in decomposition in the approximate temperature range 100-150 C. and then extracting the acids.

3. In a process for improving the yield in the production of dibasic and monobasic acids from unsaturated fatty acids selected from the group consisting of oleic acid, linoleic acid and mixtures of oleic acid and linoleic acid, the steps of ozonizing the unsaturated fatty acids in the presence of an amount of water in the approximate range of one to six times by Weight of the unsaturated fatty acids at reaction temperatures in the approximate range of 4049 C. and solvents subjecting the resulting ozonides to oxidative decomposition in the approximate temperature range 100-150 C. employing a gaseous References Cited in the file of this patent FOREIGN PATENTS 565,158 Germany Nov. 26, 1932 741,739 Great Britain Dec. 14, 1955 165,032 ,Australia Sept. 6, 1955 OTHER REFERENCES 

1. IN A PROCESS FOR THE PRODUCTION OF DIBASIC AND MONOBASIC ACIDS FROM UNSATURATED FATTY ACIDS SELECTED FROM THE GROUP CONSISTING OF OLEIC ACID, LINOLEIC ACID AND MIXTURES OF OLEIC ACID AND LINOLEIC ACID IN A SOLVENT, THE STEPS OF OXONIZING THE UNSATURATED FATTY ACIDS IN THE PRESENCE OF AN AMOUNT OF WATER IN THE APPROXIMATE RANGE OF ONE TO SIX TIMES BY WEIGHT OF THE UNSATURATED FATTY ACID AND SOLVENTS, SUBJECTING THE RESULTING OZONIDES TO OXIDATIVE DECOMPOSITION IN THE APPROXIMATE TEMPERATURE RANGE 100-150*C. AND THEN EXTRACTING THE ACIDS. 